Solid-State Welding Processes

What is welding?.What is welding?. Welding is a metal joining process which produces Welding is a metal joining process which produces

coalescence of metals by heating them to suitable coalescence of metals by heating them to suitable temperatures with or without the application of temperatures with or without the application of pressure or by the application of pressure alone, pressure or by the application of pressure alone, and with or without the use of filler material. and with or without the use of filler material.

Welding is used for making permanent joints. Welding is used for making permanent joints.

It is used in the manufacture of automobile It is used in the manufacture of automobile bodies, aircraft frames, railway wagons, machine bodies, aircraft frames, railway wagons, machine frames, structural works, tanks, furniture, boilers, frames, structural works, tanks, furniture, boilers, general repair work and ship building.general repair work and ship building.

Solid State Welding Solid State Welding Coalescence of part surfaces is achieved by: Coalescence of part surfaces is achieved by:

Pressure alone, or Pressure alone, or Heat and pressure Heat and pressure

If both heat and pressure are used, heat is If both heat and pressure are used, heat is not enough to melt work surfacesnot enough to melt work surfaces

For some Solid State Welding processes, time For some Solid State Welding processes, time is also a factoris also a factor

No filler metal is added No filler metal is added

Each Solid State Welding process has its own Each Solid State Welding process has its own way of creating a bond at the faying surfacesway of creating a bond at the faying surfaces

Solid state welding:Solid state welding:

Friction weldingFriction welding

Ultrasonic weldingUltrasonic welding

Roll weldingRoll welding

Explosive weldingExplosive welding

Friction Welding Friction Welding Solid State Welding process in which coalescence is Solid State Welding process in which coalescence is

achieved by frictional heat combined with pressure achieved by frictional heat combined with pressure

When properly carried out, no melting occurs at When properly carried out, no melting occurs at faying surfacesfaying surfaces

No filler metal, flux, or shielding gases normally usedNo filler metal, flux, or shielding gases normally used

Can be used to join dissimilar metalsCan be used to join dissimilar metals

Widely used commercial process, amenable to Widely used commercial process, amenable to automation and mass production automation and mass production

Friction Welding

Figure Friction welding (FRW): (1) rotating part, no contact; (2) parts Figure Friction welding (FRW): (1) rotating part, no contact; (2) parts brought into contact to generate friction heat; (3) rotation stopped and brought into contact to generate friction heat; (3) rotation stopped and

axial pressure applied; and (4) weld createdaxial pressure applied; and (4) weld created..

Applications / Limitations of Friction Applications / Limitations of Friction WeldingWelding

Applications:Applications: Shafts and tubular partsShafts and tubular parts Industries: automotive, aircraft, farm equipment, Industries: automotive, aircraft, farm equipment,

petroleum and natural gas petroleum and natural gas

Limitations:Limitations: At least one of the parts must be rotationalAt least one of the parts must be rotational Flash must usually be removedFlash must usually be removed Upsetting reduces the part lengths (which must Upsetting reduces the part lengths (which must

be taken into consideration in product design)be taken into consideration in product design)

Ultrasonic Welding Ultrasonic Welding

Two components are held together, oscillatory Two components are held together, oscillatory shear stresses of ultrasonic frequency are applied shear stresses of ultrasonic frequency are applied to interface to cause coalescence to interface to cause coalescence

Oscillatory motion breaks down any surface films to Oscillatory motion breaks down any surface films to allow intimate contact and strong metallurgical allow intimate contact and strong metallurgical bonding between surfaces bonding between surfaces

Although heating of surfaces occurs, temperatures Although heating of surfaces occurs, temperatures are well below melting temperatureare well below melting temperature

No filler metals, fluxes, or shielding gases No filler metals, fluxes, or shielding gases Generally limited to lap joints on soft materials such Generally limited to lap joints on soft materials such

as aluminum and copper as aluminum and copper

Ultrasonic Welding

Figure Ultrasonic welding (USW): (a) general setup for Figure Ultrasonic welding (USW): (a) general setup for a lap joint; and (b) close‑up of weld area.a lap joint; and (b) close‑up of weld area.

Ultra Sonic Welding ApplicationsUltra Sonic Welding Applications

Wire terminations and splicing in electrical Wire terminations and splicing in electrical and electronics industry and electronics industry Eliminates need for solderingEliminates need for soldering

Assembly of aluminum sheet metal panelsAssembly of aluminum sheet metal panels

Welding of tubes to sheets in solar panelsWelding of tubes to sheets in solar panels

Assembly of small parts in automotive Assembly of small parts in automotive industryindustry

Roll WeldingRoll Welding

Solid State Welding process in which pressure Solid State Welding process in which pressure sufficient to cause coalescence is applied by sufficient to cause coalescence is applied by means of rolls, either with or without external means of rolls, either with or without external heat heat

Variation of either forge welding or cold welding, Variation of either forge welding or cold welding, depending on whether heating of workparts is depending on whether heating of workparts is done prior to process done prior to process If no external heat, called cold roll weldingIf no external heat, called cold roll welding If heat is supplied, hot roll welding If heat is supplied, hot roll welding

Roll Welding

Figure. Roll welding (ROW).Figure. Roll welding (ROW).

Roll Welding Applications Roll Welding Applications

Cladding stainless steel to mild or low alloy steel Cladding stainless steel to mild or low alloy steel for corrosion resistancefor corrosion resistance

Bimetallic strips for measuring temperatureBimetallic strips for measuring temperature

"Sandwich" coins for U.S mint "Sandwich" coins for U.S mint

Explosion Welding Explosion Welding

Solid State Welding process in which rapid Solid State Welding process in which rapid coalescence of two metallic surfaces is caused by the coalescence of two metallic surfaces is caused by the energy of a detonated explosiveenergy of a detonated explosive

No filler metal usedNo filler metal used

No external heat applied No external heat applied

No diffusion occurs - time is too shortNo diffusion occurs - time is too short Bonding is metallurgical, combined with mechanical Bonding is metallurgical, combined with mechanical

interlocking that results from a rippled or wavy interlocking that results from a rippled or wavy interface between the metals interface between the metals

Explosive Welding

Commonly used to bond two dissimilar Commonly used to bond two dissimilar metals, in particular to clad one metal metals, in particular to clad one metal on top of a base metal over large areason top of a base metal over large areas

Figure Explosive welding (EXW): (1) setup in the parallel configuration, and (2) during detonation of the explosive charge.

REFERENCES:REFERENCES:

www.welding-advisors.comwww.welding-advisors.com

www.wikipedia.com www.wikipedia.com

www.welding-technology-machines.infowww.welding-technology-machines.info

www.keytometals.com www.keytometals.com